A variety of machines carry out their function using multiple and complex motions. Examples include medical imaging machines such as CAT scanners and MRI machines; industrial machinery such as multiple-axis profilers, lathes, and presses; and robots such as manufacturing robots used to assemble cars and “animatronic” type robots used in the toy and motion picture industries. The complexity of a particular machine depends on the number and complexity of motions it must perform, which in turn depends on the nature of the task the machine must perform.
Robots are now commonly used to perform very complex tasks, and as a result robots are among the most complex machines. A particular robot's design depends on the task it will perform and the constraints imposed on the design. Industrial robots, which are among the most complex, have few or no constraints on weight, space, noise, or power consumption. Other robotic applications such as robotic toys (dolls, etc) have more severe constraints, including cost, space, size, weight, noise and power consumption.
All a robot's movements are driven by actuators such as motors, whether electric, hydraulic, pneumatic, or otherwise. Usually, the number of motors needed increases with the complexity of the motions required of the robot. If the robot must perform a large number of independent movements, then the only way to do this is to have separate, and separately controlled, motors driving each motion. This arrangement has several disadvantages. The large number of motors means higher cost, higher weight, greater space requirements, and greater power consumption. Moreover, each motor has an inherently slow response time because, when activated, it must overcome the inertia of its own components and the inertia of the mechanisms it actuates. Thus, for the robot to have an adequate response time, careful synchronization of motors is necessary. Poor reliability may also be a problem because of the large number of motors and moving parts in the robot.
Today's design trend in robotic toys is to create animated dolls that closely mimic life, which requires the doll to be able to perform many independent movements. For a human robotic doll to truly mimic life, for example, would require independent motion of arms, legs, eyes, facial expression and so on. To date, the only way to create truly independent robotic movements is with one or more motors driving each movement, as is done in industrial robots. Such an arrangement is nearly impossible with robotic toys because of the design constraints mentioned above. For example, with many motors in a small robotic doll it is difficult to insulate all the noise created by the motors. It is also difficult to meet constraints such as power consumption and weight. Toys must also be produced cheaply so that the average consumer can afford to buy one. Often, it is simply impossible to put so many motors inside the limited space available. To date, no robotic doll is capable of more than a small number of truly independent motions.
Various attempts have been made to simulate independent motion in toys. For example, Tiger Electronics has sold a doll under the trademark FURBY that has a number of moving facial features. Each facial feature is coupled to a separate cam driven by an electric motor. The cams create a mechanical program that allows the facial features to move in a predetermined sequence. The movement of the facial features corresponds to an electronically generated speech pattern emitted by the doll.
U.S. Pat. No. 5,158,492 issued to Rudell et al. discloses an animated doll with a number of appendages that move relative to a torso. The appendages are coupled to an electric motor by a plurality of cams and gears. The cams and gears create a mechanical program that defines a sequence of movements for the appendages. The electric motor is actuated by a light beam transmitted by a toy camera. The appendages of the Rudell toy move to a new position each time the user “snaps” the camera to simulate a model poising for pictures.
The movements of the FURBY and Rudell toys are both limited by the mechanical program of the cams and gears. For example, the arms and head of the Rudell toy always move in the same limited sequence. It would be desirable to provide independent movement of the appendages or features to create a more “life-like” toy. The appendages can be de-coupled from each other to provide independent actuation by providing more electric motors. Additional motors increase the cost of producing the toy. The inclusion of additional motors also reduces the reliability of the toy.
Given the design trends and constraints involved in the design of small robotic toys, it is desirable to be able to produce a robot having many independent movements driven by a single motor. More broadly, it is desirable to have the ability to produce and independently control multiple power outputs from a single power input. Multiple power outputs from a single power input are not unknown. Independent control of multiple outputs is possible, but usually uses some form of clutch to engage and disengage the output from the input. Such clutches, however, require a substantial power input to engage and disengage. The power input to the clutch is usually provided by a motor of some sort, thus defeating the purpose of trying to reduce the number of motors in the system. Such an arrangement is smaller, lighter, and cheaper. Even in large robotic systems that are not as constrained, or in other machinery that involves a number of complex movements, a reduction in the number of motors would provide serious cost and space reductions and reliability improvements.
There is thus a need in the art for an apparatus that can minimize the number of motors in a particular machine while still allowing the machine to perform many independent movements so that it can carry out all its functions. For example, there is a need for an animated toy that contains independently actuated features and appendages powered by a single motor. The present invention provides such an apparatus.